The Mettler Electronics TENS 210 is two-channel battery-operated TENS unit that provides continuous, modulated and burst modes. Pulse frequency and width may be set independently. Each unit comes with a carrying case, set of four V-Trode™ self-adhesive electrodes, a 9 volt battery and instructions. The TENS 210 is easy to use, light weight and high quality. Intensity, duration, number per second, and modulation of those impulses can be altered with easy-to-use controls or switches, all in a lightweight package.